US10256830B2ActiveUtilityPatentIndex 57
Converter circuit with current interface and measuring device with such respective converter circuit
Est. expiryDec 21, 2032(~6.5 yrs left)· nominal 20-yr term from priority
H03M 1/0612H03M 1/66
57
PatentIndex Score
1
Cited by
60
References
47
Claims
Abstract
A converter circuit includes a current interface with a control input, with a current signal output and a current output. The converter circuit includes a micro-processor with a measuring signal input for the digital measuring signal, with a current signal input connected to the current signal output of the current interface, and with a control output connected to the control input of the current interface. The current interface lets the signal current flow through the current output and simultaneously adjust both the amperage to a stationary amperage level corresponding to a control value currently applied to the control input, and to output a sequence of current values at the current signal output. The micro-processor is designed to generate a measuring value sequence on the basis of the digital measuring signal and use it as the basis from which to generate a control value sequence and issue it at the control output as well as to monitor and/or check the current interface using the control value sequence and the current value sequence.
Claims
exact text as granted — not AI-modifiedThe invention claimed is:
1. A converter circuit transforming a digital measuring signal representing a temporal course of a changing physical and/or chemical measurand into an analogue measure value signal dependent on said digital measuring signal, said analogue measure value signal exhibiting a signal current, whereby an amperage of said signal current represents a measuring value for the measurand; said converter circuit comprising:
a current interface, with a control input, with a current signal output, and with a current output; and a micro-processor with a measuring signal input for the digital measuring signal, with a current signal input connected to the current signal output of the current interface, and with a current signal output connected to the current signal output of the current interface;
said current interface being configured for letting the signal current flow through the current output while adjusting the amperage of the signal current to a current value currently applied to the control input to an appropriate stationary amperage level in such a way as to make each of the stationary amperage levels dependent on a respective control value as determined by a characteristic curve function of the current interface as well as for outputting at the current signal output a current value sequence, said current value sequence representing a temporal course of the signal current amperage and said current value sequence being a sequence of digital current values representing the current amperage for different points in time;
said micro-processor being adapted to generate, based on the digital measuring signal at the measuring signal input, a measuring value sequence, said measuring value sequence representing a temporal course of the measurand for different points in time and said measuring value sequence being a sequence of digital measuring values each momentarily representing the measurand in turn, as well as to output a control value sequence at the control output based on the measuring value sequence, said control value sequence being a sequence of digital control values for the current interface; and
said micro-processor being adapted to monitor and/or check the current interface based on the control value sequence and the current value sequence.
2. The converter circuit according to claim 1 , further comprising:
a volatile data memory to save digital measured values and/or digital control values, with the micro-processor being set to temporarily save digital control values, as well as digital current values in the data memory.
3. The converter circuit according to claim 1 , wherein:
said micro-processor is adapted to check the current interface based on the control value sequence and the current value sequence, namely: to determine a deviation between a control value and at least one corresponding digital current value and/or to determine to what extent said current value deviates from said control value and/or to determine a current characteristic curve function according to which the current interface adjusts said stationary amperage levels in relation to said digital control values and/or to determine whether or to what extent a current characteristic curve function used by said current interface to adjust the stationary amperage levels subject to said digital control values deviates from a previously determined characteristic curve function determined for the current interface.
4. The converter circuit according to claim 1 , wherein:
the current interface includes a release input and the micro-processor includes a release output connected to said release input of the current interface; and whereby the current interface is adapted to output the sequence of current values on the current signal output after a control command has been applied to the release input that activates the current signal output, and the micro-processor is adapted to generate control command to activate the current signal output and issue it at the release output.
5. The converter circuit according to claim 4 , wherein:
the current interface is adapted to temporarily not issue a sequence of current values at the current signal output.
6. The converter circuit according to claim 5 , wherein:
the current interface is adapted not to issue a sequence of current values at the current signal output after a deactivating control command is applied to the release input; and
the micro-processor is adapted to generate a control command to deactivate the current signal output and issue it at the release output.
7. The converter circuit according to claim 1 , wherein:
the converter circuit is adapted to be operated in a normal operation mode over some time, during which normal operation mode the measurand is modified only over time within a pre-determined measuring range, with a minimum range limit, for the pre- set measuring value for measurand and a determined maximum range limit, pre-set by the determined highest measuring value for measurand, and during which normal operation mode the micro-processor only outputs control values at the control output which cause the current interface to adjust the amperage of the signal current in such a way that the stationary amperage levels are each found within a pre-set measuring range, that is pre-set in that it corresponds with the measuring range for the measurand, therefore having a first limit current value, corresponding to the minimum range threshold, and a second limit current value, corresponding to the maximum range threshold, which differs from the first limit current value.
8. The converter circuit according to claim 7 , wherein: the first limit current value is 4 mA or less.
9. The converter circuit according to claim 7 , wherein:
the second limit current value is 20 mA or more.
10. The converter circuit according to claim 7 , wherein:
the converter circuit is adapted to be operated in a special operating mode for at least some of the time, during which special operation mode the micro-processor outputs such control values at the control output that cause the current interface to adjust the amperage of the signal current in such a way that the stationary amperage levels are outside the pre-set measuring range.
11. The converter circuit according to claim 10 , wherein:
the converter circuit is adapted to switch from normal operation mode to special operation mode.
12. The converter circuit according to claim 10 , wherein:
the micro-processor is adapted to output a control value at the control output to determine at least one replacement coefficient, with said control value causing the current interface to adjust the amperage of the signal current to a stationary amperage level that is lower than the lower of the two limit amperages of the measuring range; and/or
the micro-processor is adapted to output a control value at the control output to determine at least one replacement coefficient, with said control value causing the current interface to adjust the amperage of the signal current to a stationary amperage level that is higher than the higher of the two limit amperages of the measuring range.
13. The converter circuit according to claim 10 , wherein:
the micro-processor is adapted to switch automatically from a normal operating mode to said special operating mode.
14. The converter circuit according to claim 10 , wherein:
the micro-processor is adapted to switch controlled externally from a normal operating mode to said special operating mode.
15. The converter circuit according to claim 7 , wherein:
the converter circuit is adapted to be operated in a start-up mode that starts up the micro-processor.
16. The converter circuit according to claim 15 , wherein:
the micro-processor is designed to check the current interface during start-up mode.
17. The converter circuit according to claim 15 , wherein:
the micro-processor is adapted to check the current interface during start-up mode by issuing a live-zero-control value at the control output, namely a control value that causes the current interface to adjust amperage of the signal current in such a way that the corresponding stationary amperage level relates to a live-zero-value, namely an amperage signaling the live zero point of the converter circuit corresponding to the lowest of the two limit amperages.
18. The converter circuit according to claim 17 , wherein:
the micro-processor is adapted to check automatically the current interface during start-up mode by issuing a control value that deviates from the live-zero-control value causing the current interface to adjust the amperage of the signal current in such a way that the corresponding stationary amperage level relates to a current value above the lowest of the two limit amperages.
19. The converter circuit according to claim 18 , wherein:
the micro-processor is adapted to check the current interface during start-up mode automatically, by using the live-zero-control value, a digital current value corresponding to the live-zero-control value, the control value deviating from the live- zero-control value, as well as at least one digital current value corresponding to said digital current value to determine a current characteristic curve function that regulates the adjustment of the stationary amperage levels subject to the digital control values by the current interface and by comparing said current characteristic curve function with a pre-set characteristic curve function; and/or
the micro-processor is adapted to check the current interface during start-up mode automatically by determining both, a deviation between the live-zero-control value and the respective digital current value and a deviation between the other control value deviating from the live-zero-control value and the respective digital current value, and by determining whether each of the deviations found is within or outside a tolerance range representing admissible deviations.
20. The converter circuit according to claim 1 , wherein:
the micro-processor is adapted to determine a transducer error based on the sequence of control values and the sequence of current values, esp. based on the saved control values, as well as the saved digital current values.
21. The converter circuit according to claim 1 , wherein:
the micro-processor is adapted to determine the control values of the control value sequence based on a calculation rule determined by at least two pre-set, currently valid coefficients (A 1 , . . . , A N ) according to a polynomial function
W
D
,
j
=
∑
k
=
1
N
A
k
·
X
D
,
j
k
-
1
=
A
1
+
A
2
·
X
D
,
i
+
…
+
A
N
·
X
D
,
j
N
-
1
as the functional value of an function of at least one of the digital measuring values of the sequence of measuring values.
22. The converter circuit according to claim 21 , wherein:
the micro-processor is adapted to adjust, based on the sequence of control values and the sequence of current values, said calculation rule to a current characteristic curve function used by the current interface to adjust the stationary amperage levels subject to the digital control values.
23. The converter circuit according to claim 22 , wherein:
the micro-processor is adapted to adjust said calculation rule to a current characteristic curve function such that a deviation of the current characteristic curve function from a previously determined characteristic curve function for the current interface is compensated.
24. The converter circuit according to claim 21 , wherein:
the micro-processor is adapted to occasionally determine at least one replacement coefficient (A′ M ) for at least one of the currently valid but still to be replaced coefficients (A M ∈ {A 1 , . . . , A N }).
25. The converter circuit according to claim 24 , wherein:
the converter circuit is adapted to be operated in a special operating mode for at least some of the time, during which special operation mode the micro-processor outputs such control values at the control output that cause the current interface to adjust the amperage of the signal current in such a way that the stationary amperage levels are outside a pre-set measuring range, and the micro-processor is adapted to determine the replacement coefficient in said special operating mode.
26. The converter circuit according to claim 25 , wherein:
the micro-processor is adapted to switch from a normal operating mode to said special operating mode in order to determine the replacement coefficient.
27. The converter circuit according to claim 25 , wherein:
the micro-processor is adapted to determine the replacement coefficient in said special operating mode in such a way that for the determination of at least the replacement coefficient at least two different control values are issued by the micro-processor, at least one of which causes the current interface to adjust the amperage of the signal current in such a way that the respective stationary amperage level is below the lowest of the two limit amperages, and/or at least one of which causes the current interface to adjust the amperage, of the signal current in such a way that the respective stationary amperage level is higher than the higher of the two limit amperages.
28. The converter circuit according to claim 24 , further comprising:
a persistent data memory, wherein: the micro-processor is adapted to store said at least one replacement coefficient within said persistent data memory.
29. The converter circuit according to claim 21 , wherein:
the micro-processor is designed to determine at least one replacement coefficient (A′ M ) for at least one of the currently valid but nonetheless to be replaced coefficients (A M ∈ {A 1 , . . . , A N }), based on a first control value (W D,j ) determined by the calculation rule governed by a calculation rule corresponding to said momentarily valid coefficients (A 1 , . . . , A N ), issued at the control output and valid at least at a first point in time (t j ) and at least one first digital current value (I D,j ) issued by the current interface at its current signal output and based on at least one second control value (W D,j+1 ) issued at control output compliant with the calculation rule determined by said momentarily valid coefficients (A 1 , . . . , A N ) and valid at a second point in time (t j+n ) which differs from the first control value (W D,j ) and at least one second digital current value (I D,j+n ) issued by the current interface at its current signal output.
30. The converter circuit according to claim 29 , wherein:
the micro-processor is designed to generate a control value sequence using the at least one replacement coefficient instead of the coefficient to be replaced.
31. The converter circuit according to claim 29 , wherein:
the micro-processor is designed to determine,
a replacement coefficient (A′ 1 ) for a first coefficient (A 1 ∈ {A 1 , . . . , A N }) to be replaced compliant with a first calculation rule for replacement coefficients, using a first control value (W D,j ) and the first digital current value (I D,j ) as well as the second control value (W D,j+1 ) and the second digital current value (I D,j+n ):
A
1
′
=
A
1
-
1
-
I
D
,
j
+
n
-
I
D
,
j
1
-
I
D
,
j
W
D
,
j
=
A
1
-
1
-
A
2
A
2
′
1
-
I
D
,
j
W
D
,
j
(
n
>
0
&
W
D
,
j
≠
W
D
,
j
+
n
)
,
as well as a replacement coefficient (A′ 2 ) for a second coefficient to be replaced (A 2 ∈ {A 1 , . . . , A N }) as per a second calculation rule for a replacement coefficient:
A
2
′
=
A
2
·
W
D
,
j
+
n
-
W
D
,
j
I
D
,
j
+
n
-
I
D
,
j
(
n
>
0
&
W
D
,
j
≠
W
D
,
j
+
n
)
;
and then generate the control value sequence (w D ) using both the first replacement coefficient (A′ 1 →A 1 ) instead of the first coefficient (A 1 ) to be replaced and using the second replacement coefficient (A′ 2 →A 2 ) instead of the second coefficient (A 2 ) to be replaced.
32. The converter circuit according to claim 1 , wherein:
the converter circuit is adapted to at least occasionally check, based on the sequence of control values and the sequence of current values, whether a stationary amperage level corresponds to the respective pre-set control value and/or to what extent a stationary amperage level deviates from the control value set.
33. The converter circuit according to claim 1 , wherein:
the micro-processor is designed to determine the control values (W D,j ) of the control value sequence as a linear function of one of the digital measuring values (X D,j ) of the measuring value sequence based on a polynomial function
W
D
,
j
=
∑
k
=
1
N
=
2
A
k
·
X
D
,
j
k
-
1
=
A
1
+
A
2
·
X
D
,
ij
of polynomial degree N-1=1 governed by two precisely predetermined, currently valid coefficients (A 1 , A 2 ).
34. The converter circuit according to claim 1 , further comprising:
a persistent data memory.
35. A measuring device, comprising:
a measuring sensor to capture a physical and/or chemical measurand changing over time and to generate at least one analogue measuring signal representing the temporal course of said measurand; a well as measuring device electronics electrically coupled to the sensor and adapted to convert the analogue measuring signal in a digital measuring signal representing said analogue measuring signal and, consequently, a temporal course of said measurand, wherein the measuring device electronics includes a converter circuit according to claim 1 .
36. The measuring device according to claim 35 , wherein:
the measuring device electronics includes:
a first connecting terminal adapted to be electrically connected to a first conduit external from the converter circuit; and
a second connecting terminal adapted to be electrically connected to a first conduit external from the converter circuit.
37. The measuring device according to claim 36 , wherein:
the current output of the current interface includes two connecting electrodes, of which connecting electrodes a first connecting electrode is connected electrically to the first connecting terminal and a second connecting electrode connected to the second connecting terminal.
38. The measuring device according to claim 36 , further comprising:
a display element controlled by the micro-processor to display measured values generated by the micro-processor and to display a pair of values consisting of a current value and a control value and/or a deviation of a current value from a control value and/or to display a transducer error.
39. The measuring device according to claim 36 , further comprising:
a third connecting terminal adapted to be electrically connected to a third conduit external from the converter circuit; and
a fourth connecting terminal adapted to be electrically connected to a fourth conduit external from the converter circuit.
40. The measuring device according to claim 39 , wherein:
the voltage input of the energy supply circuit comprises two connecting electrodes, of which connecting electrodes the first connecting electrode is connected to the third connecting terminal and a second connecting electrode to the fourth connecting terminal.
41. The measuring device according to claim 35 , wherein:
said measuring device electronics further comprise an energy supply circuit with an input and at least one output, said energy supply circuit being adapted to supply a useful voltage at said output to operate the micro-processor and/or to operate the current interface.
42. The measuring device according to claim 41 , wherein:
the energy supply circuit is designed to carry at least a part of the signal current and use it to supply the useful voltage to operate the micro-processor and/or operate the current interface.
43. The converter circuit according to claim 1 , wherein:
the micro-processor is adapted to monitor and/or check the current interface based on the control value sequence and the current value sequence based on at least temporarily saved control values as well as at least temporarily saved digital current values.
44. The converter circuit according to claim 1 , wherein:
the micro-processor is adapted to monitor and/or check the current interface based on a deviation between a control value and at least determine one respective digital current value.
45. The converter circuit according to claim 1 , wherein:
the micro-processor is adapted to monitor and/or check the current interface by determining to what extent a current value deviates from its corresponding control value.
46. The converter circuit according to claim 1 , wherein:
the micro-processor is adapted to monitor and/or check the current interface by determining a current characteristic curve function used by the current interface to adjust stationary amperage levels depending on the digital control values.
47. The converter circuit according to claim 1 , wherein:
the micro-processor is adapted to monitor and/or check the current interface by determining if or to what extent a current characteristic curve function used by the current interface to adjust stationary amperage levels deviates from an earlier characteristic curve function of the current interface.Cited by (0)
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